Google Inc is entering the online music market almost a decade too late to pose a threat to Apple Inc, the largest seller of songs on the Web.

The service, scheduled to be unveiled at a Google event in Los Angeles today, will let users store songs online and listen to tracks on multiple devices, people familiar with the matter said. Apple opened the iTunes store in 2003 and made popular the legal downloading of music from the Internet.

Google’s new challenge to Apple escalates the rivalry between the two companies, already locked in a fight for smartphone users and mobile-advertising customers.

The internet- search giant also faces budding competition from Amazon.com Inc, which has bolstered its music-download and storage service, and Spotify Ltd, whose partnership with Facebook Inc has buoyed US membership this year.

“They’re coming into this market rather late in the game, where there are large, established players,” said Ray Valdes, an analyst at Gartner Inc in San Jose, California.

“You can say it’s a saturated market.”

Google, the owner of the biggest internet search engine, has expanded into music, television and movies to bolster sales of devices running its Android mobile software. The company, based in Mountain View, California, is also seeking rights for its Google+ social-network users to share music with each other, people familiar said.